View Poll Results: Which year to build a SC for
Multiple Choice Poll. Voters: 104. You may not vote on this poll
To build a supercharger kit or not?
12-22-2004, 02:53 PM
#77
Race Car
Ok let me get this straight, you're saying resonance charging does *not* increase the volume (i.e. amount) of the air that goes *into* the cylinders? Wanna bet on that one?
You're joking, right?? The resonance valve only increases the movement of the air and to some degree the speed at which the air moves. However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas. Only by compressing the air or liquid or gas can more fit into the same container. As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
You're joking, right?? The resonance valve only increases the movement of the air and to some degree the speed at which the air moves. However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas. Only by compressing the air or liquid or gas can more fit into the same container. As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
12-22-2004, 02:53 PM
#78
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Hi 1999,
Connect a vaccum gauge to your engine and see if you have engine vacuum while cruising at 100 mph. If you do (and you should) there is little to no boost entering the engine. The by-pass vale IS ALWAYS OPEN when there is vacuum.
So I thought positive pressure controlled the by-pass valve- i.e. say your compressor is generating lots of boost, you shift, close your throttle body, pressure build up behind the plate bypass valve kicks open to relieve pressure and prevents damage to the turbo compressor. Why would the by-pass valve be always open when there's vacuum? Why would this be a good design?
No I DO mean the square of 6.
Square of 6 = 6^2= 36, make no sense
power of 6 = x^6, which is more like it...
And just WHY would you want a power curve that "SUCKS"? No Turbo Charger of the same boost will come close to giving you the low end power that a Cetrifuge blower will. The power curve of the centrifuge is as smooth as you can get. Also, having a boost level of more than 2.5 at 3500 rpm on a static engine of 11.3:1 is hardly a low boost level.
Sorry we disagree here. Modern design turbo systems that are well matched to the engine are VERY responsive. Most good systems designed to peak in the 9psi range peak well less than 3000 rpm these days. Repeat - we're talking full 9psi from less than 3000 all the way to redline. Massive torque.
But we each have our own preference, but having installed and run all the various SC's available, I will stay with the cetrifuge style.
Godspeed my friend. IMHO centrifugal has some definite downsides, but then again it's better than no SC or turbo at all. I'm sure your car will rip up the track quite nicely.
Connect a vaccum gauge to your engine and see if you have engine vacuum while cruising at 100 mph. If you do (and you should) there is little to no boost entering the engine. The by-pass vale IS ALWAYS OPEN when there is vacuum.
So I thought positive pressure controlled the by-pass valve- i.e. say your compressor is generating lots of boost, you shift, close your throttle body, pressure build up behind the plate bypass valve kicks open to relieve pressure and prevents damage to the turbo compressor. Why would the by-pass valve be always open when there's vacuum? Why would this be a good design?
No I DO mean the square of 6.
Square of 6 = 6^2= 36, make no sense
power of 6 = x^6, which is more like it...
And just WHY would you want a power curve that "SUCKS"? No Turbo Charger of the same boost will come close to giving you the low end power that a Cetrifuge blower will. The power curve of the centrifuge is as smooth as you can get. Also, having a boost level of more than 2.5 at 3500 rpm on a static engine of 11.3:1 is hardly a low boost level.
Sorry we disagree here. Modern design turbo systems that are well matched to the engine are VERY responsive. Most good systems designed to peak in the 9psi range peak well less than 3000 rpm these days. Repeat - we're talking full 9psi from less than 3000 all the way to redline. Massive torque.
But we each have our own preference, but having installed and run all the various SC's available, I will stay with the cetrifuge style.
Godspeed my friend. IMHO centrifugal has some definite downsides, but then again it's better than no SC or turbo at all. I'm sure your car will rip up the track quite nicely.
12-22-2004, 03:09 PM
#79
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You're joking, right??
Nope.
The resonance valve only increases the movement of the air and to some degree the speed at which the air moves.
Resonance charging has to do with air momentum and the intake valve opening/closing. Essentially air rushing in compresses (i guess like a spring) when the intake valve shuts due to actual momentum of the air flowing down the intake track. These pressure waves can be 'tuned' by varying the length of the intake runner as RPM's (and intake valve open/close frequency) increases. The end result is these pressure waves promote better filling of the intake chamber - volume of the cylinder is always the same, BUT volume of air filling the chamber increases - if you took a measure from the AFM with and without resonant tuning at a given rpm, you'll get a higher airflow reading from the engine with the tuned intake. Your 996 has a variable intake (varioram) that changes the intake properties as rpm increases.
However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas.
The physical volume dimensions of the cylinder never change, yes
Only by compressing the air or liquid or gas can more fit into the same container.
Well air is a gas. And by the laws of hydraulics, liquids won't compress at all.
As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
Absolutely.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
Yup that's one way, but it's not just O2, you're increasing the density of air by cooling it.
Nope.
The resonance valve only increases the movement of the air and to some degree the speed at which the air moves.
Resonance charging has to do with air momentum and the intake valve opening/closing. Essentially air rushing in compresses (i guess like a spring) when the intake valve shuts due to actual momentum of the air flowing down the intake track. These pressure waves can be 'tuned' by varying the length of the intake runner as RPM's (and intake valve open/close frequency) increases. The end result is these pressure waves promote better filling of the intake chamber - volume of the cylinder is always the same, BUT volume of air filling the chamber increases - if you took a measure from the AFM with and without resonant tuning at a given rpm, you'll get a higher airflow reading from the engine with the tuned intake. Your 996 has a variable intake (varioram) that changes the intake properties as rpm increases.
However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas.
The physical volume dimensions of the cylinder never change, yes
Only by compressing the air or liquid or gas can more fit into the same container.
Well air is a gas. And by the laws of hydraulics, liquids won't compress at all.
As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
Absolutely.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
Yup that's one way, but it's not just O2, you're increasing the density of air by cooling it.
12-22-2004, 03:12 PM
#80
Race Car
So I thought positive pressure controlled the by-pass valve- i.e. say your compressor is generating lots of boost, you shift, close your throttle body, pressure build up behind the plate bypass valve kicks open to relieve pressure and prevents damage to the turbo compressor. Why would the by-pass valve be always open when there's vacuum? Why would this be a good design?
Because the bypass valve is vacuum operated. Why do you need boost while cruising? Just a waste of gas.
Square of 6 = 6^2= 36, make no sense
power of 6 = x^6, which is more like it...
I meant to type "square root'. Sorry about that.
Sorry we disagree here. Modern design turbo systems that are well matched to the engine are VERY responsive. Most good systems designed to peak in the 9psi range peak well less than 3000 rpm these days. Repeat - we're talking full 9psi from less than 3000 all the way to redline. Massive torque.
You should tell the TT's that have less lower end power than me that. It might make them feel better.
Like I said before, I expect Turbo's to become used less in perfomance cars because of they are not as efficient as the SC.
I would say that my 0 -60 time on street tires of 4.01 seconds and 0 -102 time of 9 seconds proves the bottom end perfromance of my SC.
Because the bypass valve is vacuum operated. Why do you need boost while cruising? Just a waste of gas.
Square of 6 = 6^2= 36, make no sense
power of 6 = x^6, which is more like it...
I meant to type "square root'. Sorry about that.
Sorry we disagree here. Modern design turbo systems that are well matched to the engine are VERY responsive. Most good systems designed to peak in the 9psi range peak well less than 3000 rpm these days. Repeat - we're talking full 9psi from less than 3000 all the way to redline. Massive torque.
You should tell the TT's that have less lower end power than me that. It might make them feel better.
Like I said before, I expect Turbo's to become used less in perfomance cars because of they are not as efficient as the SC.
I would say that my 0 -60 time on street tires of 4.01 seconds and 0 -102 time of 9 seconds proves the bottom end perfromance of my SC.
12-22-2004, 03:15 PM
#81
Race Car
Nope.
The resonance valve only increases the movement of the air and to some degree the speed at which the air moves.
Resonance charging has to do with air momentum and the intake valve opening/closing. Essentially air rushing in compresses (i guess like a spring) when the intake valve shuts due to actual momentum of the air flowing down the intake track. These pressure waves can be 'tuned' by varying the length of the intake runner as RPM's (and intake valve open/close frequency) increases. The end result is these pressure waves promote better filling of the intake chamber - volume of the cylinder is always the same, BUT volume of air filling the chamber increases - if you took a measure from the AFM with and without resonant tuning at a given rpm, you'll get a higher airflow reading from the engine with the tuned intake. Your 996 has a variable intake (varioram) that changes the intake properties as rpm increases.
However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas.
The physical volume dimensions of the cylinder never change, yes
Only by compressing the air or liquid or gas can more fit into the same container.
Well air is a gas. And by the laws of hydraulics, liquids won't compress at all.
As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
Absolutely.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
Yup that's one way, but it's not just O2, you're increasing the density of air by cooling it.
So, I guess we agree compression IS REQUIRED.
The resonance valve only increases the movement of the air and to some degree the speed at which the air moves.
Resonance charging has to do with air momentum and the intake valve opening/closing. Essentially air rushing in compresses (i guess like a spring) when the intake valve shuts due to actual momentum of the air flowing down the intake track. These pressure waves can be 'tuned' by varying the length of the intake runner as RPM's (and intake valve open/close frequency) increases. The end result is these pressure waves promote better filling of the intake chamber - volume of the cylinder is always the same, BUT volume of air filling the chamber increases - if you took a measure from the AFM with and without resonant tuning at a given rpm, you'll get a higher airflow reading from the engine with the tuned intake. Your 996 has a variable intake (varioram) that changes the intake properties as rpm increases.
However, no matter what speed you fill a specific size container (in this case the cylinder) the container will only hold a maximum volume...whether it is air or liquid or gas.
The physical volume dimensions of the cylinder never change, yes
Only by compressing the air or liquid or gas can more fit into the same container.
Well air is a gas. And by the laws of hydraulics, liquids won't compress at all.
As a matter of fact. the higher in altutude you drive your car, the less total volume of air you have in the cylinders due to less atmospheric pressure. This is one of the reasons that high flying aircraft often use turbo or SC engines to create more volume.
Absolutely.
If you want to increase the amount of O2 in the same amount of air, one way is to make the air cooler.
Yup that's one way, but it's not just O2, you're increasing the density of air by cooling it.
So, I guess we agree compression IS REQUIRED.
12-22-2004, 03:22 PM
#82
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I think there is some confusion here. 1999P911, are you solely referring to mechanical methods of compression? If not, your arguments are based on semantics, as we all agree that resonance tuning compressses the air/fuel charge by utilising pressure waves inherent in the moving mass of air/fuel.
If, on the other hand, you suggest that resonance tuning is just about turbulence, and that you can only get more air/fuel into a cylinder via mechanical compression (ie suprcharging/turbocharging) then you are wrong.
Either way, we all agree compression is required to induce more air/fuel into a cylinder.
If, on the other hand, you suggest that resonance tuning is just about turbulence, and that you can only get more air/fuel into a cylinder via mechanical compression (ie suprcharging/turbocharging) then you are wrong.
Either way, we all agree compression is required to induce more air/fuel into a cylinder.
12-22-2004, 04:05 PM
#83
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Originally Posted by PorschePhD
98993,
Keep in mind this truly was a question to the masses of do we build it. Lets say I could nothing more than what TPC has done performance wise. Are you guys wanting something else that is done with a more efficient system and with true programming and larger injectors?
Keep in mind this truly was a question to the masses of do we build it. Lets say I could nothing more than what TPC has done performance wise. Are you guys wanting something else that is done with a more efficient system and with true programming and larger injectors?
12-22-2004, 05:01 PM
#84
I don't know if it would mean it would cost more than TPC's, there seems to be a lot of margin built into their kits. In addition to their margin, there's significant additional effort ($) in addition to the kit to end up with a finished product. I'd still be interested if the performance were the same but the solution was more elegant.
Kind of like "A Toyota will get you there but I'd rather drive my Porsche."
Kind of like "A Toyota will get you there but I'd rather drive my Porsche."
12-22-2004, 07:04 PM
#86
I hear you. Here's my train of thought..
If the COGS for the TPC kit is ~2K for the charger itself, $200 for the black box, $200 for the 7th injector, then they've got ~3500 in every kit to cover their R&D at a $6.5K sales price. To the end user add the cost of installation (lets say $1500), then any competitor has a lot of room to work within. The TPC kit seems to come in ~8K for people without intercooler with installation. Even if the additional labor involved with changing injectors is double the typical TPC install, he's got a LOT of room to work with to undercut TPC and still have a theoretically better approach.
BTW, I'm not bashing TPC, just trying to encourage some competition...
If the COGS for the TPC kit is ~2K for the charger itself, $200 for the black box, $200 for the 7th injector, then they've got ~3500 in every kit to cover their R&D at a $6.5K sales price. To the end user add the cost of installation (lets say $1500), then any competitor has a lot of room to work within. The TPC kit seems to come in ~8K for people without intercooler with installation. Even if the additional labor involved with changing injectors is double the typical TPC install, he's got a LOT of room to work with to undercut TPC and still have a theoretically better approach.
BTW, I'm not bashing TPC, just trying to encourage some competition...
12-22-2004, 09:15 PM
#87
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Agreed...competition is a good thing. There is indeed room, and if remapping/injectors give a marketing advantage if not a performance advantage, that's good too.
I understand the TPC kit is not really a fully finished out kit, either. Seems like a bit of extra fab work and parts here and there. A more complete kit would be good too.
I understand the TPC kit is not really a fully finished out kit, either. Seems like a bit of extra fab work and parts here and there. A more complete kit would be good too.
12-27-2004, 06:34 PM
#88
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Look guys, if you do build a SC kit, do the wise thing and use a Whipple SC.
It is BY FAR the best choice for a custom kit. Yeah, several companies out there have used the ancient Eaton design (even with it's Gen 2, 3, or 4 it still doesn't come close to the Whipple in terms of power/efficiency/low temperature gain).
The Whipple has a very flat powerband from idle to redline, strong low-mid range power (much better than the Centrifugal units), and good top-end power (much better than the Eaton).
The Whipple combines the only known benefits of the Eaton and Centrifugal SC units into a single reliable SC.
Having owned and modified numerous turbocharged and a few SC'ed cars, the Whipple is the smartest choice/alternative to a large ball bearing turbocharger.
And no, it's not expensive, just $1750 for the 2300AX model itself.
Yeah, if I was to put a 3.6 in a 914 or a '71 911, then yes, I would probably choose a centrifugal SC for maximum top-end power, since the engine would have more than enough power before the SC made any boost.
It is BY FAR the best choice for a custom kit. Yeah, several companies out there have used the ancient Eaton design (even with it's Gen 2, 3, or 4 it still doesn't come close to the Whipple in terms of power/efficiency/low temperature gain).
The Whipple has a very flat powerband from idle to redline, strong low-mid range power (much better than the Centrifugal units), and good top-end power (much better than the Eaton).
The Whipple combines the only known benefits of the Eaton and Centrifugal SC units into a single reliable SC.
Having owned and modified numerous turbocharged and a few SC'ed cars, the Whipple is the smartest choice/alternative to a large ball bearing turbocharger.
And no, it's not expensive, just $1750 for the 2300AX model itself.
Yeah, if I was to put a 3.6 in a 914 or a '71 911, then yes, I would probably choose a centrifugal SC for maximum top-end power, since the engine would have more than enough power before the SC made any boost.
01-08-2005, 02:34 AM
#89
Track Day
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Deposit details: $1,500
Build it & they will come.
For those who wish to progress now: Stephen informs me the deposit's $1,500. So, per the thread-starting post, if he receives eight deposits, development will start, & we should have finished products ready ~six weeks after.
Excellent discussion has been raised from this thread, & ideally PorschePhD would answer all questions here and now. Until then, maybe this will help: In a recent e-mail, he wrote,
That can be argued either way, with valid points on both sides. However, I read Adrian Streather's recent post about his work-in-progress, his 993 book. He makes a strikingly similar statement,
I acknowledge books & engines are quite different (start with price tag comparisons & go from there), however, I suspect both of these talented Porsche enthusiasts' work will have the similarity of being worth waiting for & trusting in. For those of you that agree & have the funds & interest now, please consider contacting ImagineAuto to make a deposit.
Just my thoughts. Make deposits, & he'll build it.
For those who wish to progress now: Stephen informs me the deposit's $1,500. So, per the thread-starting post, if he receives eight deposits, development will start, & we should have finished products ready ~six weeks after.Excellent discussion has been raised from this thread, & ideally PorschePhD would answer all questions here and now. Until then, maybe this will help: In a recent e-mail, he wrote,
"[...] it does me no good to chat about the design if I need to change it. I then get blasted because it was this and I said it was that."
"I do not answer direct questions about content whilst I am writing because it changes and evolves."
Just my thoughts. Make deposits, & he'll build it.
02-07-2005, 09:34 PM
#90
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Steve, I am very interested in your project! Having spent the first fourty-five years(give or take for time in school and Air Force) of almost fifity-three, do I know you ? I have'nt owned thirty Porsche's, only four but thirty years in PCA. As an old time Bunker and BHR client, I'm not familiar with your shop? Where exactly are you in KC? With family and friend's in town I'm there at least once a month and would like to stop by. TKS PT
